Coin Flipper Calculator — Simulate Coin Tosses
Flip up to 200 coins at once — fair or biased — and see the full H/T sequence, heads and tails counts, longest streaks and a donut chart. Hit "Flip Again" for a new random result.
flips
Tails: 4 — click Flip Again for a new simulation
6/10
headsHeads (6)
60%
Tails (4)
40%
How does this calculator work?
This calculator simulates n independent Bernoulli trials each with P(head) = p using a seeded LCG. It displays the full H/T sequence, head/tail counts, longest runs, and a donut chart. Expected heads = n × p; actual results vary by binomial chance. Click "Flip Again" to re-simulate.
Formula
How this is calculated
Each coin flip is an independent Bernoulli trial: heads with probability p (0.5 for a fair coin) and tails with probability 1−p. The simulation uses a seeded linear congruential generator (LCG) — a fast, deterministic pseudo-random number generator — so each (number of flips, P(head), flip-count) combination produces a reproducible sequence. Clicking "Flip Again" increments an internal counter that changes the seed, giving a new independent sequence.
For a fair coin and a large number of flips, the law of large numbers guarantees the fraction of heads will converge toward 0.5, but individual runs can deviate substantially from expectation — especially for small n. Ten flips could easily give 3 heads or 8 heads; both are well within normal binomial variation. The "Expected heads" figure shows n × p, the theoretical long-run average.
Longest head and tail streaks are important intuition-builders: people systematically underestimate how long streaks typically get by chance. For 100 fair coin flips the expected longest head run is approximately log₂(100) ≈ 6–7 consecutive heads. The donut chart compares actual heads vs tails to give a quick visual sense of deviation from expectation.
Frequently asked questions
The calculator uses a seeded LCG pseudo-random number generator. It produces sequences that pass statistical randomness tests and are unpredictable to the user, but it is not cryptographically random. For deciding something important, use a physical coin or a hardware random number generator.
That's normal binomial variation. For 10 flips of a fair coin, getting 7 or more heads happens about 17% of the time — nearly one in five runs. Flip a larger number of coins and the fraction of heads will converge toward 50%, but short runs will always show apparent streaks and imbalances.
Set P(head) to any value between 0 and 1. A value of 0.6 means the coin lands heads 60% of the time on average. Real-world physical coins are extremely close to 0.5, but spin-biased or edge-biased tosses can deviate slightly.
Also known as
TG we-Calculate Editorial Team. (2026). Coin Flipper Calculator — Simulate Coin Tosses [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/coin-flipper-calculator
TG we-Calculate Editorial Team. "Coin Flipper Calculator — Simulate Coin Tosses." TG we-Calculate. 2026. https://we-calculate.com/calculator/coin-flipper-calculator.
TG we-Calculate Editorial Team, "Coin Flipper Calculator — Simulate Coin Tosses," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/coin-flipper-calculator
@misc{wecalculate_coin_flipper_calculator, title = {Coin Flipper Calculator — Simulate Coin Tosses}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/coin-flipper-calculator}}, year = {2026}, note = {TG we-Calculate} }
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